Operations involving the handling and processing of fluids entail fluids being contained in various types of fluid chambers. These fluid chambers may take the form of pipes, conduits, tubes, or open channels for transporting fluids under the influence of gravity or of pumping systems, or they may take the form of vessels, tanks, or vats for carrying out various chemical or other processes. Monitoring process variables within a fluid chamber is a key component of overall process assessment and control, and such assessment and control may require injection and/or extraction of materials to or from the chamber. While access ports for measurement and control may be designed within a fluid chamber initially, such is not always the case. In some cases, process conditions and other considerations may warrant placement of access ports at different places and for different purposes than those provided in the initial fabrication of a chamber.
There are numerous challenges to designing access devices for fluid chambers, particularly for industries processing food, drinks, pharmaceuticals, and bio-products, etc. First, access devices should be designed to maintain hygienic conditions in the area where the access device penetrates the fluid chamber. Maintenance of hygienic conditions is promoted by not having crevices or voids where process products may collect and stagnate creating biological risks. Second, in many cases the fluid contained within the chamber will be at a substantial pressure. Accordingly, the access device should be robust and designed such that it and the seal provided can be securely held in place without being adversely affected hygienically by the pressure within the chamber.
There are known devices that are designed for gaining access to fluid chambers used for processing/conveying fluids under hygienic requirements. Most of the devices are provided with an elastomeric seal for forming a sealed relationship between the access device and the edge of an opening in the fluid chamber. The design of these access devices is generally that, when installed, the seal lies between the wall of the chamber and a support structure secured to the chamber. When the access device is installed, the support structure compresses the seal axially against the surface of the chamber.
The geometry of the access device in the vicinity of the chamber opening where the seal is located often introduces localized zones of fluid stagnation within the chamber. These zones can have a negative hygienic impact on the fluid contained within the chamber since they cannot be effectively cleaned in situ by routine Clean-In-Place (CIP) procedures. This results in the need to dismantle the support structure and access device in order to carry out manual cleaning procedures on the dismantled components at frequent intervals. These procedures are both labor intensive and time consuming.
Another disadvantage of this kind of access device installation geometry is the restriction it places on the choice of installation location within the process.
A further problem encountered by the known forms of access device is that an increase in the fluid pressure within the chamber will have a tendency to move the support structure that compresses the seal away from the seal and the chamber opening resulting in a reduction in the compression of the seal. This produces an increased hygienic risk from fluid ingress into the seal contact areas.